Vehicle headlamp



March 24,1942. ,K. D. scoTT ET AL 2,277,563

VEHI CLE HEADLAMP Filed Nov. 9, 1940 2 Sheets-Sheet l 1nven'kofs:

Kenneth D. Scofit,

Patented Mar. 24, 1942 2,277,563 VEHICLE HEADLAMP Kenneth D. Scott and Daniel K. Wright, Cleveland Heights, Ohio, assignors to General'Electric Company, a corporation of New York Application November 9, 1940, Serial No. 365,022 4 Claims. (01. 240-413) Our invention relates in general to vehicle headlights such as are used on automobiles to illuminate the. roadway. More specifically, our invention relates to a non-glaring vehicle headlight especially useful when driving in foggy or adverse weather.

Vehicle headlamps and so-called fog lamps in general use at present comprise a reflector,

mounted. In both types of lamps, however, there is a certain amount of uncontrolled light, part of which is directed upwardly above the horizontal. The sources of this uncontrolled light are many, particularly in the case where a separate lamp unit is mounted within the reflector, but the principal sources are the bases of the prisms on the lens, especially where downbending prisms are employed, and the direct rays from the light source itself. The uncontrolled light, besides producing undesirable glare rays which impair the vision of approaching drivers, is particularly annoying when driving in foggy weather inasmuch as it produces a nimbus of illuminated fog particles of which that portion above the horizontal acts to greatly impair the drivers visibility of the roadway, because of the reflection of some of the light rays back into the eyes of the driver. I

One object of our invention is to provide a vehicle headlamp in which substantially all the uncontrolled light .is eliminated from the light beam.

Another object of our invention is to provide a vehicle headlamp in which substantially all upwardly directed rays of light are eliminated from the light beam. 4

Still another object of our invention is to provide a highlyeflicient fog lamp which will provide considerably better visibility of the roadway,

. when driving in foggy weather, than that heretofore obtainable.

A further object of our invention is to provide a fluted prismatic lens for vehicle headlamps having substantially no inherent sources of upwardly directed or glare rays.

A still further object of our invention is to provide a vehicle headlamp having a fluted prismatic lens and which will roduce a light beam characterized by the absence therefrom of substantially all upwardly directed light rays.

A feature of the invention is the coating of all the draft surfaces, corners and edges at the bases of the horizontally-extending verticalbending prisms on the lens with an opaque material at least the rearwardly facing surface of which, i. e., that surface of the opaque coating facing the headlight reflector, is made non-reflecting to thereby absorb the light rays falling thereon. Another feature of .the invention is the use of a light-absorbing shield arranged within the reflector forwardly of and above the light source or filament for the purpose of shielding all direct rays emanating from the light source in an upward direction above the horizontal.

Further Objects and advantages of our invention will appear from the following description of species thereof and from the accompanying drawings in which: I

Fig. 1 is a front view of a vehicle headlamp or fog lamp comprising our invention; Fig. 2 is a vertical sectional view taken on the line 22 of Fig. 1; Fig; 3 is a fragmentary perspective view of the filament mount and the associated light shield; Fig. 4 is a view similar to Fig. 2 of a modified form of vehicle headlight comprising our invention; and Fig. 5 is a fragmentary view, on an enlarged scale, of a portion of the lens according to the invention.

Referring to Figs. 1-3, the invention is there shown as applied to a vehicle headlamp of the "sealed beam" type such as described and claimed in United States Patents No. 2,148,314 and No.

13 in the form of a coil or coiled-coil of a suitable refractory metal, preferably tungsten, mounted within the envelope. The inner surface H of the reflector section II is shaped to conform to a paraboloid, and is provided with a coating l5 of suitable reflecting material, such as aluminum or silver, to thereby form a reflectmg surface. The filament I3 is preferably in the form of alinear coil mounted substantially at the focus of the reflecting surface l5, and extending transversely of the reflector axis 1-1- and lying in the horizontal axial plane h-h of the reflector. The filament is firmly supported in this position by means of a pair of leading-in wires l6, l1 to which the ends of the filament are electrically connected. The said leading-in wires I6, I1 extend through openings I8 in the reflector section II adjacent the apex thereof, and are hermetically sealed through metal cups or thimbles l9 which are sunk and fused into the glass around the said openings l8 so as to form a hermetic seal therebetween. The outer ends of the leading-in wires l6, 11 are connected to terminals 20 on a base 2| secured to the rear of the reflector section II at the apex thereof. The bulb or envelope H) is evacuated and filled with gas by means of an exhaust tube 22 located at the apex of the reflector section II, the said to spread the light rays horizontally, and suitable horizontally extending prisms 24 adapted to bend or refract the light rays vertically. The

flutes and prisms are preferably formed on the inner surface of the lens I2, although they may be provided on the outer surface if desired. The said prisms 24 are preferably arranged in a series of horizontal rows extending entirely across the lens so that the bases or intersections 25 of the prisms form a series of horizontal bands ex- .tending entirely across the lens. Normally, glare is caused by the lens action of the corners or edges 25a and fillets 251) at the bases 25 of the prisms. As more fully explained in the Howard et a1. Patent No. 2,177,216, the said edges and fillets concentrate horizontal light rays into upwardly directed individual beams.

In accordance with the invention, all the draft surfaces, corners or edges 25a, and fillets 25b (Fig. comprising the bases or intersections 25 of the prisms 24 are coated with a suitable opaque material such as graphite, having a non-reflecting surface facing the reflector, to thereby form.

a series of horizontally extending narrow opaque bands 26, As a result, all the light rays that normally would strike such draft surfaces, corners and edges at the bases or intersections of the prisms, and which would result in uncontrolled light, are completely absorbed by the opaque bands 26 of graphite, such material providing a dull black surface from which there is practically no reflection of the rays back onto the reflecting surface l5.v Thus, all sources of uncontrolled light within the lens 12 itself are entirely eliminated. Instead of graphite, other suitable opaque materials, such as copper, silver or aluminum, may be used as the coating material. However, where the surfaces of the coating material are normally reflecting in character, then those surfaces of the opaque bands facing the reflector ll must be suitably treated, for instance by oxidation thereof, to render the same non-reflecting, otherwise the light rays striking such bands would be reflected back onto the reflector II and then again reflected into the beam as uncontrolled light. The graphvite coating 26 is applied to the lens l2 by spraying a graphite solution thereon and allowing the same to dry, a mask being used during the spraylight shield 21 is mounted in front of and above the filament I3, the shield being so shaped and arranged as to intercept all the direct rays from the filament which are directed upwardly above the horizontal plane through the lowermost portion of the filament, i. (2., all those direct rays substantially within the half-cone of light defined by the filament (as the vertex), the upper half of the periphery of the reflecting surface l5, and the horizontal plane through the filament. The shield 21 may be made of any suitable shape or form which will accomplish the intended purpose, but is preferably shaped as a lune, preferably in the form of a quadrant of a hollow sphere, with its concave surface facing the filament. The shield is positioned with oneedge 28 disposed substantially in a horizontal plane passing through the lowermost portion of the filament and the other edge 29 disposed substantially in a vertical plane extending transversely of the lamp axis r-r. with respect to the filament as to insure the cutting-off by the shield of all the upwardly projected direct rays of the filament without caus ing any appreciable interference with the rays directed towards the reflecting surface l5. It will be obvious that, instead of forming the shield 21 in the shape of a lune, it may consist merely of a half-disc or semi-circular plate suitably mounted in front of 'and above the filament to cut off the direct rays therefrom in the intended manner. i

The shield 21 thus provides means simple in construction for cutting out the direct rays from the lamp filament which hinder visibility to the driver of the vehicle in foggy or adverse weather and which also cause dangerous glare to a pedestrian or driver of another vehicle approaching, without at the same time materially diminishing the total illumination from the headlamp. This result arises from the fact that the shield 21 does not cut off the light rays to the reflector, these rays being reflected outwardly from the headlamp without hindrance, just as in the case of an ordinary headlamp.

Inasmuch as the shield 21 is preferably nonreflecting in character, no particular care is necessary as to the mounting of the shield with respect to the filament l3 since there is no reflection of light therefrom back onto the reflecting surface I5. The only requirement, in such case, is that the shield be properly mounted so as to intercept the direct rays from the filament in the desired manner. However, where the shield 21 is made reflecting in character, then in such case the shield is preferably mounted with its center of curvature slightly above the filament so that any light reflected by the shield is condensed at a point above the focus of the reflector and, on striking the reflecting surface 15, is deflected downwardly in the beam in the same manner as would obtain if the filament were mounted above focus.

To eliminate from the light beam all upward- 1y projected direct rays from the filament 13, a relatively small and preferably non-reflecting The light shield 21 is supported in position .by

means of a supportarm 30 (Fig. 3) which is welded to one or the other of the leading-in wires l6, l1. The shield 21 and the arm 30 are preferably formed as one piece by stamping from a thin strip of nickel, the arm being stamped with longitudinally extending ribs 3| for strengthening purposes. The shield is provided with a coating of suitable material to render it non-reflecting. For this purpose we prefer to employ .a dullblack non-reflecting ceramic material, although other materials, such as Aquadag," may The edge 29 is so located the eyes of the driver.

be used instead. The ceramic material is applied to the shield 21 in the form of a solution,

The coated shields are then fired in an oven,

resulting in the formation of a hardened dull black ceramic coating on the shield.

To further minimize the amount of uncontrolled light emanating from the lamp, a small portion of the inner surface M of the reflector section I I at the apex thereof, including the holes I8 through which the leading-in wires pass and the hole formed by the exhaust tube 22, is left free of reflecting material l5, as shown at 32. As a consequence, the reflection of light from the rounded corners of such holes and the inaccurate surfaces thereadjacent is greatly minimized, thus practically eliminating such areas as sources of uncontrolled light.

The combination, in accordance with the invention, of the opaque bands or coatings'26 on the lens, and the light shield 21, as well as the non-reflecting area 32 at the apex of the reflector section ll, thus insures the elimination of practically all uncontrolled light from the light beam and provides a headlamp which, when equipped with a lens of proper design and mounted and aimed in the proper manner, will project a beam of light located entirely below the horizontal and having no upwardly directed rays above the horizontal whatsoever. Such a beam is especially suitable and effective for driving in foggy or adverse weather, for there are no upwardly directed rays illuminating the fog particles above the horizontal so as to cause a blinding of the driver by the reflection of such rays back into Furthermore, such a beam is very effective as a trafiic or passing beam because of the absence therefrom of all upwardly directed light rays which would normally produce glare and impair the vision of approaching drivers. Obviously, to obtain the full advantages of such a beam for driving in foggy weather, the beam should notbe supplemented in any way by any other light beam from other lamps on the vehicle which would project upwardly directed rays of light.

Although any suitable lens and deflector arrangement may be employed to project a controlled'beam of light below the horizontal, the lens l2 preferably employed, is one commonly referred to as a traffic or passing lens and having the following prescription-z A Horizontal Horizontal Vertical prism spread prism a. up. 8: i righllii 2 up.. 1 rig C 1% down 12 None. 1). 1 down 24 None. F l% down 24 None. F up. 6 3 right G. 3 1Z5; rlight i j 11? 1 4 lEl't. 34 up 1 1% left.

L y; up 1 1}? right. M 2 down 18 N one: N. 3 down 24 None. O l 2 down 24 None.

When the lamp in is provided with a lens conforming to the above prescription, and the lamp is aimed slightly downward and to the right so that the axis r-r of the reflector is directed approximately two degrees down from the horizontal and approximately three degrees to the right of the vertical, then a beam will be projected fiector 34.

the top of which, in the lower right quadrant is substantially coincident with the horizontal, and in the lower left quadrant is depressed approximately two degrees or thereabouts below the horizontal.

It will be observed that the lens l2 according be desirable, where the lamp is to be used as a' passing lamp, to also opaque the bases or intersections of such left bending prisms.

Fig. 4 illustrates one way in which the invention may be applied to a headlamp employing a separate lamp 33 mounted Within a separate metal reflector 34. The lamp 33 comprises a small sealed bulb 35 containing a filament 36 similar to the filament l3 in Figs. 1-3 and electrically connected by leading-in wires 31 to the terminals 38 of a base 39. The lamp 33 is mounted in the reflector 34 with the base 39 extending through an opening 40 in the reflector at the apex thereof, and with the filament 35 disposed approximately at the focus of the reflector, the same as in the previous form of the invention. The reflector 34 likewise has the same shape as that of the reflecting surface I5 in Figs. l-3, i. e., paraboloidal so as to reflect the rays from the filament forwardly in a direction substantially parallel to the reflector axis T4. The mouth of the reflector. is covered by a lens l2 of the same prescription as the lens l2 in Figs. 13 and provided with similar opaque bands or coatings 25 on the prism bases 25.

To intercept the direct rays from the filament 36 which are directed upwardly above the horizontal plane through the lowermost portion of the filament, a portion of the upper half of the tip or bowl portion of the bulb 35 is provided with a coating 4| of opaque material similar in configuration to the shield 21 in Figs. 1-3, the lower edge 42 of the coating lying in a horizontal plane through the lowermost portion of the filament and the upper edge 43 lying in a transverse plane slightly forward of the filament so that the coating intercepts only the upwardly projected direct rays from the filament and does not out off the rays which are directed towards the re- The coating material employed is preferably one which will not reflect light, such as a dull black ceramic material fired onto the glass bulb.

While we have shown and described the invention in connection with a headlamp having only a single light source, it may be advantageously 'employed in headlamps having two light sources,

such as are in widespread commercial use at present, where one filament is disposed slightly above the other and is used to produce a passing beam, while the lower filament is used to produce a driving beam. In such a headlamp, the shield 21 or 4|, as the case may be, is arranged to intercept all the upwardly projected direct rays from the upper or passing beam filament only. Obviously, a certain proportion of the upwardly projected direct rays from the lower or driving beam filament will also be intercepted by the-shield, but such rays form a very small proportion of the total amount of light in the driving beam. With such a two filament arrangement, a headlamp is provided which will produce an efficient driving beam as well as an especially efficient passing beam which is, furthermore, particularly effective for driving in foggy weather because of the absence therefrom of all upwardly directed rays of light.

What we claim as new and desire to secure by Letters Patent of the United States is:

l. A light projecting device comprising a lightconcentrating reflector, a light source mounted in definite relation to said reflector, and a lens covering the mouth of said reflector and having one of its surfaces divided into a plurality 'of horizontal rows of horizontally extending prisms for bending the light rays from said reflector in a vertical direction, said prisms having base portions separating adjacent rows of prisms, said base portions having rounded edges and fillets which normally concentrate horizontal light rays into upwardly directed individual beams, a plurality of horizontal bands of opaque material on said lens entirelycovering the said base portions of said prisms including said edges and fillets, and a light shield located adjacent said light source and constructed and arranged to intercept substantially all direct rays therefrom which are directed upwardly beyond the periphery of said reflector and above a horizontal plane through said light source.

2. A light projecting device comprising a sealed envelope including a concave glass reflector portion and a glass lens portion sealed together at their peripheries by fusion, said lens having on one of its surfaces a plurality of vertically spaced horizontally extending prisms for bending the light rays from said reflector portion in a vertical direction, the bases of said prisms having rounded edges and fillets which normally concentrate horizontal light rays into upwardly directed individual beams, a light source mounted within said envelope in definite optical relation to said reflector portion, a covering of opaque material on the base portion, of said prisms including said edges and fillets and having a nonreflecting surface facing said reflector portion,

- and a relatively small light shield located adjacent said light source and constructed and arranged to intercept substantially all direct rays therefrom which are directed upwardly beyond the periphery of therefiector portion and above a horizontal plane through said light source.

3. A light projecting device comprising a lightconcentrating reflector, a lens covering the mouth of said reflector and having on one of its surfaces a plurality of vertically spaced horizontally extending prisms for bending the light rays from said reflector in a vertical direction, said base portions having rounded edgesand fillets which normally concentrate horizontal light rays into upwardly directed individual beams, a coating of opaque material on the base portions of said prisms including said edges and fillets and having a non-reflecting surfacefacing said reflector, and an electric incandescent lamp mounted in said reflector, said lamp comprising a relatively small sealed bulb and a concentrated filament within said bulb and disposed in definite optical relation to said reflector, said bulb having a coating of opaque material on the upper front portion thereof arranged to intercept substantially all direct rays from said filament which are directed upwardly beyond the periphery of said reflector and above a horizontal plane through said filament.

theirperipheries by fusion, alight source mounted within said envelope in definite optical relation to said reflector portion and having its opposite ends connected to a pair of leading-in wires extending through openings in said reflector portion located adjacent the vertex thereof, a coating of reflecting material on substantially the entire inner surface of said reflector portion except for a small area at the vertex thereof within which the said openings are included, said lens having on one of its surfaces a plurality of vertically spaced horizontally extending prisms for bending the light rays from said reflector portion in a vertical direction, said base portions having rounded edges and fillets which normally concentrate horizontal light rays into upwardly directed individual beams, a covering'of opaque material on the base portions of said prisms including said edges and fillets and having a non-reflecting surface facing said reflector portion, and a relatively small light shield located adjacent said light source and constructed and arranged to intercept substantially all direct rays therefrom which are directed upwardly beyond the periphery of said reflector portion and above a horizontal plane through said light source.

KENNETH D. SCOTT. DANIEL K. WRIGHT. 

